There is a feedforward control system for performing feedforward control using a controller to an object to be controlled (controlled object). In an ideal feedforward control system, a target value is given to a system, as a control value for controlling a controlled object, and a physical quantity matching the target value is output from the controlled object.
FIG. 12 is a block diagram illustrating a configuration of the ideal feedforward control system. A target value r is given to a controller of a system 101 including the controller and a controlled object, and the controller drives the controlled object with a drive signal in accordance with the target value r, whereby an output yr corresponding to the target value r is obtained from the system 101.
For example, the above feedforward control system is configured in a power generation system, in which a power generation system including a power generator and its controller is the system 101. When an amount of power demand is input as the target value r to a controller for controlling an amount of power generation of the power generator, power yr of about the same amount as the power demand is output from the power generator.
In an actual situation, a target value to be given to a system (that is, an amount of output of a controlled object currently required) is unknown, and a predicted value obtained by predicting the target value with a predetermined prediction model has to be given to the system in many cases.
For example, since a current amount of power demand (an amount of power actually required) cannot be accurately obtained in a case of the power generation system described above, a predicted value obtained with a predetermined prediction model has to be given to the power generation system.
FIG. 13 is a block diagram illustrating a configuration of a control system controlled with a predicted value. A predicted value{circumflex over (r)}  [Expression 1]obtained with a predetermined prediction model is given to a system 102. Incidentally, in the following,{circumflex over (r)}  [Expression 2]is also written as “r^.” An output yr^ depending on the predicted value r^ is obtained from the system 102.
However, in a case of controlling with the predicted value, an error occurs also in the output of the controlled object by an amount corresponding to a prediction error (that is, a difference between the predicted value and the actual target value). Therefore, a feedforward control system has been known provided with a prediction governor (predicted value shaper) for correcting (shaping) the predicted value given to the system by using a previous target value (that is, a control value actually required previously) as a result value, in order to prevent influence of the prediction error from influencing the output of the system. Here, the result value is not a previous output value, but is a control value actually required, and the result value is independent of the output value.
FIG. 14 is a block diagram illustrating a configuration of a control system provided with a prediction governor. A previous target value (result value) r is given to a prediction governor 201, in addition to a predicted value r^. The prediction governor 201 calculates a control value v on the basis of these predicted value r^ and result value r, and outputs the control value v to a system 103. An output yv corresponding to the control value v is obtained in the system 103.
For example, in a case of the power generation system described above, the predicted value r^ of the amount of power demand obtained by applying the weather, the temperature, and the like to the prediction model, is corrected by using the result value r of, for example, a few minutes ago (that is, the control value actually required a few minutes ago) in the prediction governor 201, and can be given to the system 103. With such a feedforward control system, balancing control is performed.